Question: Simplify the following expression: $a = \dfrac{n}{9} + \dfrac{2n}{3}$
Explanation: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $9$ and $3$ $\lcm(9, 3) = 9$ $ a = \dfrac{1}{1} \cdot \dfrac{n}{9} + \dfrac{3}{3} \cdot \dfrac{2n}{3} $ $a = \dfrac{n}{9} + \dfrac{6n}{9}$ $a = \dfrac{n +6n}{9}$ $a = \dfrac{7n}{9}$